There are any number of possible excursions from Prague, many within an hour or two's journey by train or car. The variety of scenery may come as a surprise, from the craggy uplands of Český Ráj and the Krkonože (Giant) Mountains to the woodland slopes of the Berounka Valley. Further south around Třeboň is a wetland area of lakes and carp-rearing ponds, an ideal habitat for water birds; and there are other surprises in store: a fairy-tale castle on an isolated hill top, a gloomy limestone cave with dripping stalactites, a charming Renaissance town hall at the centre of a busy market square. The elegant 19th-century resort of Karlovy Vary is famous for its hot mineral springs; Plzeň and České Budějovice are both centres of the brewing industry, and the vineyards of Mělník date back to the reign of Charles IV.